The invention relates to line rail type self-driven tunnel-lining nondestructive detecting system and method. The line rail type self-driven tunnel-lining nondestructive detecting system comprises suspension devices, a driving device, track wheels, a displacement sensor and a detecting-antenna system; a track steel wire is arranged on the suspension device fixed at the starting and tail ends of one detection line, the driving device moves on the track steel wire through the track wheels, and the detecting-antenna system used for recording tunnel-lining reflection waveform on the detection line and the displacement sensor used for labeling sensed displacement values on a waveform scale are mounted on the driving device. By the arrangement, danger of workers in high detection due to the fact that the detection line is too high, non-level property of the detection line due to the antenna holding manually, uneven detection speed and the antennal not closely attached during detection are effectively avoided during tunnel-lining nondestructive detection, error about detection location and waveform interval is reduced, and meanwhile, due to connection of a displacement recording device, the length of the detected detection line is accurately marked on the detection waveform, and workload is reduced.